ABSTRACT Growing evidence shows that hereditary cancer predisposition syndromes affect 5-10% of cancer patients, with heightened risk among patients who develop cancer at a young age, especially adolescents and young adults (AYAs). Genetic counseling is therefore recommended for all AYAs with new cancer diagnoses, for whom results can lead to future cancer screening, risk-reducing surgeries, and reproductive counseling. Testing can also have a domino effect, identifying other affected relatives and reducing cancer risk in entire families. AYAs require unique considerations when communicating cancer risk due to wide variability in developmental and emotional maturity. Genetic counseling necessitates complex cognitive and affective processing from AYAs, ideally resulting in an active ownership of their condition and a commitment to life-long health behavior change. This tall order comes as AYAs are forming their identity, gaining parental independence, and considering future childbearing ? often under the shadow of enormous personal or family losses from cancer. These factors complicate AYAs' ability to weigh tradeoffs of genetic testing and screening recommendations ? sometimes with tragic consequences. Unfortunately, there have been few if any efforts to optimize cancer risk communication and decision-making for AYAs. The goal of this project is to develop, implement and test an AYA-specific intervention for cancer risk communication and decision-making. Our interdisciplinary team of experts in health communication, cancer genetics, oncology, and pediatric psychology from 4 major Cancer Risk Programs will develop AYA-RISE (Risk Information and Screening Education), a web-based intervention comprised of (1) an interactive chatbot designed to communicate genetic information to AYAs in developmentally appropriate ways; and (2) an individualized patient portal, serving as an educational resource and longitudinal repository for cancer risk and screening information. Iterative user testing with qualitative feedback from AYAs will be used to optimize the program prior to conducting a type I hybrid implementation effectiveness trial of AYA-RISE. Our aims are: Aim 1: To refine and pilot AYA-RISE, adapting implementation to ensure feasibility and acceptability among AYAs with cancer risk syndromes, their family members, and providers. Aim 2: To test AYA-RISE among AYAs with cancer predisposition syndromes at 4 centers to determine impact on (1) patient knowledge of cancer risk and recommended screening; (2) psychological distress; (3) patient ownership of information; and (4) follow-up for recommended care. Aim 3: To evaluate implementation outcomes of AYA-RISE, including ways that AYAs use the chatbot and patient portal, and AYA, family, and provider experiences, to facilitate future dissemination. If successful, this study will yield a scalable, patient- and family-centered intervention to improve cancer risk communication and decision-making for AYAs and their families, with an ultimate goal of cancer risk reduction.